The integration of cells into engineered devices has considerable potential in implantable biomedical therapeutics, stem cell environments and cell-based biosensors. These applications require that cells survive on or in inorganic or hybrid materials and carry out normal metabolism, proliferation and differentiation. The microenvironment immediately surrounding the cells substantially impacts cellular processes and ultimately the final fate of the cell. The presentation and characterization of bioactive molecules at the surface of inorganic and hybrid materials, therefore, is an important factor in a material's capability.
Sol-gel derived materials produced under biologically benign conditions have demonstrated an ability to serve as substrates or supports for numerous cell types including mammalian cells, bacteria, and yeast. The sol-gel method of producing amorphous inorganic or organically modified porous solids from liquid precursors is a functionally diverse technique that allows for simple manipulation of both chemical features as well as nanoscale morphology through processing procedures. Metal alkoxides, such as tetramethoxysilane, are common liquid precursors. Organically modified silica (ormosil) can be created by modifying the functional groups on the silane precursors (see Briones, et al., Physical Review Letters 2004, 93, (20)), resulting in a material that is decorated with the chemical functionality of choice.
As disclosed herein a novel sol-gel method is provided for producing biologically active peptide-modified porous silica matrices from peptide-silane precursors. A variety of materials have been prepared that have taken advantage of known cell binding peptide sequences from proteins, such as extracellular matrix proteins and cell-cell adhesion proteins, at the biointerface to enhance cell adhesion. Peptides such as the RGD group from fibronectin type III repeats, and the YIGSR peptide from laminin, enhance cell adhesion of various cell types to two dimensional materials. Previous work has generally presented such bioactive peptides as a self-assembled monolayer immobilized using various chemistries, including thiol attachment (Faucheux, et al., Biomat. 2004, 25, 2721), covalent assembly using amine linkers (Kim, T. G.; Park, T. G. Biotechnology Progress 2006, 22, 1108), or physioadsorption onto the surface of interest (Betancor, et al., Enzyme and Microbial Technology 2006, 39, 877). Controlling the percentage of the peptides at the surface is difficult to achieve, as multilayer organization and environmental factors all play a role in the efficiency of the coupling chemistry, leading to a lack of consistency from surface to surface.
Accordingly, there is a need for a sol-gel chemistry that allows for a simple single reaction vessel synthesis while allowing for precise concentration manipulation of added peptides. The present invention provides such a process, producing a sol-gel wherein one or more peptides of choice are covalently linked to the resulting film such that the peptides do not leach out of the material matrix.